Heretofore, there has been known a construction machine comprising a lower traveling body, an upper slewing body provided on the lower traveling body slewably about a slewing axis, and a work implement attached to the upper slewing body in a raisable and lowerable manner (such as a hydraulic excavator described in JP 2011-157721 A (hereinafter referred to as “Patent Literature 1”)).
In the hydraulic excavator described in the Patent Literature 1, a rear portion of the upper slewing body has a shape capable of staying within a range equal to or slightly greater than a width of the lower traveling body during a slewing movement about the slewing axis.
Specifically, the upper slewing body comprises an upper frame slewably provided on the lower traveling body, and a rear wall portion provided in a rear portion of the upper frame to cover a space over the upper frame from therebehind. The rear wall portion has a right or left end portion curved in an approximately arc shape in top plan view (this end will hereinafter be referred to as “curved portion”).
The hydraulic excavator described in the Patent Literature 1 further comprises an engine provided on the upper frame at a position in front of the rear wall portion, and an exhaust aftertreatment device configured to treat exhaust gas of the engine, and provided in front of the rear wall portion while being superposed over an interspace between the engine and the curved portion. As above, the exhaust aftertreatment device is provided at a position offset laterally from a position directly above the engine (provided over the interspace between the engine and the curved portion), so that it becomes possible to ensure a space for performing maintenance of the engine above the engine.
The exhaust aftertreatment device comprises a first treatment section capable of removing a first component contained in the exhaust gas, and a second treatment section capable of removing a second component contained in the exhaust gas.
The first treatment section and the second treatment section are supported over the upper frame, while being arranged side-by-side in a right-left (lateral) direction. In this arrangement, respective longitudinal directions of the first and second treatment sections are oriented along a front-rear direction and parallel to each other. Further, respective longitudinal edge faces (rear edge faces) of the first and second treatment sections are positioned in offset relation from each other in the front-rear direction, in conformity to a shape of the curved portion.
However, in the hydraulic excavator described in the Patent Literature 1, because the longitudinal directions of the first and second treatment sections are oriented along the front-rear direction, a relatively wide dead space is undesirably formed between the curved portion, and the longitudinal edge faces and longitudinally-extending lateral surfaces (right lateral surfaces) of the first and second treatment sections, in a top plan view.